Add spatiotemporal dithering to fog

6 files changed, 56 insertions, 5 deletions

diff --git a/2ner.cginc b/2ner.cginc
index d78e3db..bd5e743 100644
--- a/2ner.cginc
+++ b/2ner.cginc
@@ -196,8 +196,14 @@ float4 frag(v2f i, uint facing : SV_IsFrontFace
       _Raymarched_Fog_Density,

       _Raymarched_Fog_Y_Cutoff,

       _Raymarched_Fog_Dithering_Noise,

+      _Raymarched_Fog_Dithering_Noise_TexelSize,

       _Raymarched_Fog_Density_Noise,

-      _Raymarched_Fog_Density_Noise_Scale

+      _Raymarched_Fog_Density_Noise_Scale,

+      #if defined(_RAYMARCHED_FOG_HEIGHT_DENSITY)

+      _Raymarched_Fog_Height_Density_Min,

+      _Raymarched_Fog_Height_Density_Max,

+      _Raymarched_Fog_Height_Density_Power,

+      #endif

     };

     FogResult fog_result = raymarched_fog(i, fog_params);

     depth = fog_result.depth;

diff --git a/2ner.shader b/2ner.shader
index d176ea7..bff1cb0 100644
--- a/2ner.shader
+++ b/2ner.shader
@@ -820,11 +820,19 @@ Shader "yum_food/2ner"
         [HideInInspector] m_start_Raymarched_Fog("Raymarched fog", Float) = 0
           [ThryToggle(_RAYMARCHED_FOG)] _Raymarched_Fog_Enabled("Enable", Float) = 0
           _Raymarched_Fog_Steps("Steps", Range(1, 32)) = 32
+          _Raymarched_Fog_Color("Color", Color) = (0.3, 0.3, 0.3, 1)
           _Raymarched_Fog_Density("Density", Float) = 1.0
           _Raymarched_Fog_Dithering_Noise("Dithering noise", 2D) = "black" {}
           _Raymarched_Fog_Density_Noise("Density noise", 3D) = "black" {}
           _Raymarched_Fog_Density_Noise_Scale("Density noise scale", Vector) = (1, 1, 1, 0)
           _Raymarched_Fog_Y_Cutoff("Y cutoff", Float) = -1000
+
+          [HideInInspector] m_start_Raymarched_Fog_Height_Density("Height density", Float) = 0
+            [ThryToggle(_RAYMARCHED_FOG_HEIGHT_DENSITY)] _Raymarched_Fog_Height_Density_Enabled("Enable", Float) = 0
+            _Raymarched_Fog_Height_Density_Min("Height density min", Float) = 0
+            _Raymarched_Fog_Height_Density_Max("Height density max", Float) = 100
+            _Raymarched_Fog_Height_Density_Power("Height density power", Float) = 1
+          [HideInInspector] m_end_Raymarched_Fog_Height_Density("Height density", Float) = 0
         [HideInInspector] m_end_Raymarched_Fog("Raymarched fog", Float) = 0
         //endex
 
@@ -1806,6 +1814,7 @@ Shader "yum_food/2ner"
         [HideInInspector] m_start_Shadow_Casting("Cast shadows", Float) = 0
         [ThryToggle(_)] _Cast_Shadows_Enabled("Enable", Float) = 1
         [HideInInspector] m_end_Shadow_Casting("Cast shadows", Float) = 0
+        //endex
         //ifex _Wrapped_Lighting_Enabled==0
         [HideInInspector] m_start_WrappedLighting("Wrapped lighting", Float) = 0
         [ThryToggle(_WRAPPED_LIGHTING)] _Wrapped_Lighting_Enabled("Enable", Float) = 1
diff --git a/audiolink.cginc b/audiolink.cginc
index 68ddb60..d9c167a 100644
--- a/audiolink.cginc
+++ b/audiolink.cginc
@@ -1,7 +1,7 @@
 #ifndef __AUDIOLINK
 #define __AUDIOLINK
 
-#if defined(_SHATTER_WAVE_AUDIOLINK) || defined(_VERTEX_DOMAIN_WARPING_AUDIOLINK) || defined(_SSAO)
+#if defined(_SHATTER_WAVE_AUDIOLINK) || defined(_VERTEX_DOMAIN_WARPING_AUDIOLINK) || defined(_SSAO) || defined(_RAYMARCHED_FOG)
 #include "Third_Party/AudioLink.cginc"
 #endif
 
diff --git a/features.cginc b/features.cginc
index 40ed4a1..59a3ff3 100644
--- a/features.cginc
+++ b/features.cginc
@@ -315,5 +315,9 @@
 #pragma shader_feature_local _RAYMARCHED_FOG
 //endex
 
+//ifex _Raymarched_Fog_Height_Density_Enabled==0
+#pragma shader_feature_local _RAYMARCHED_FOG_HEIGHT_DENSITY
+//endex
+
 #endif  // __FEATURES_INC
 
diff --git a/fog.cginc b/fog.cginc
index bd1c1da..b1e209c 100644
--- a/fog.cginc
+++ b/fog.cginc
@@ -1,6 +1,7 @@
 #ifndef __FOG_INC
 #define __FOG_INC
 
+#include "audiolink.cginc"
 #include "cnlohr.cginc"
 #include "interpolators.cginc"
 #include "globals.cginc"
@@ -12,8 +13,14 @@ struct FogParams {
     float density;
     float y_cutoff;
     texture2D dithering_noise;
+    float4 dithering_noise_texelsize;
     texture3D density_noise;
     float4 density_noise_scale;
+#if defined(_RAYMARCHED_FOG_HEIGHT_DENSITY)
+    float height_density_min;
+    float height_density_max;
+    float height_density_power;
+#endif
 };
 
 struct FogResult {
@@ -26,7 +33,8 @@ FogResult raymarched_fog(v2f i, FogParams p)
   float3 ro = _WorldSpaceCameraPos;
   float3 rd = normalize(i.eyeVec.xyz);
 
-  ro += rd * 1E-3;
+  const float ro_epsilon = 1E-3;
+  ro += rd * ro_epsilon;
 
   float2 screen_uv = (i.pos.xy + 0.5) / _ScreenParams.xy;
   float zDepthFromMap = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, screen_uv);
@@ -44,6 +52,15 @@ FogResult raymarched_fog(v2f i, FogParams p)
     }
   }
   linearZ = min(linearZ, distance_to_y);
+  linearZ -= ro_epsilon;
+
+  float dither = p.dithering_noise.SampleLevel(point_repeat_s,
+      screen_uv * _ScreenParams.xy * p.dithering_noise_texelsize.xy, 0).r;
+
+  const float frame = ((float) AudioLinkData(ALPASS_GENERALVU + int2(1, 0)).x);
+  dither = frac(dither + PHI * frame);
+  ro += rd * dither;
+  linearZ -= dither;
 
   float step_size = linearZ / p.steps;
   float3 pp = ro;
@@ -53,15 +70,25 @@ FogResult raymarched_fog(v2f i, FogParams p)
     pp += step_size * rd;
     float cur_d = p.density_noise.SampleLevel(linear_repeat_s,
         pp * p.density_noise_scale.xyz, 0);
+
     cur_d *= p.density * step_size;
 
+#if defined(_RAYMARCHED_FOG_HEIGHT_DENSITY)
+    // Apply height-based density (branchless)
+    float t = saturate((pp.y - p.height_density_min) /
+                      (p.height_density_max - p.height_density_min));
+    float height_factor = pow(1.0 - t, p.height_density_power);
+    cur_d *= height_factor;
+#endif
+
+    cur_d = saturate(cur_d);
     d = d + (1 - d) * cur_d;
   }
 
   FogResult r;
-  r.color.rgb = 1;
+  r.color.rgb = _Raymarched_Fog_Color;
   //r.color.rgb = saturate(log(linearZ) / 5.0);
-  r.color.a = saturate(d);
+  r.color.a = d;
   //r.color.a = 1;
   r.depth = 0.0001;  // Very small depth value to render in front
   return r;
diff --git a/globals.cginc b/globals.cginc
index 22d707b..341e08b 100644
--- a/globals.cginc
+++ b/globals.cginc
@@ -536,12 +536,17 @@ float _SSAO_Bias;
 #endif  // _SSAO

 

 #if defined(_RAYMARCHED_FOG)

+float3 _Raymarched_Fog_Color;

 float _Raymarched_Fog_Steps;

 float _Raymarched_Fog_Density;

 texture2D _Raymarched_Fog_Dithering_Noise;

+float4 _Raymarched_Fog_Dithering_Noise_TexelSize;

 texture3D _Raymarched_Fog_Density_Noise;

 float4 _Raymarched_Fog_Density_Noise_Scale;

 float _Raymarched_Fog_Y_Cutoff;

+float _Raymarched_Fog_Height_Density_Min;

+float _Raymarched_Fog_Height_Density_Max;

+float _Raymarched_Fog_Height_Density_Power;

 #endif  // _RAYMARCHED_FOG

 

 #endif  // __GLOBALS_INC